Introduce con_get_fullscreen_covering_ws

This commit will also fix the following bugs:
1. click.c: Users could drag global fullscreen floating containers.
2. render.c: Floating containers would get rendered with a global fullscreen container in another
workspace.

include/con.h

@@ -120,6 +120,14 @@ Con *con_parent_with_orientation(Con *con, orientation_t orientation);
  */
 Con *con_get_fullscreen_con(Con *con, fullscreen_mode_t fullscreen_mode);
 
+/**
+ * Returns the fullscreen node that covers the given workspace if it exists.
+ * This is either a CF_GLOBAL fullscreen container anywhere or a CF_OUTPUT
+ * fullscreen container in the workspace.
+ *
+ */
+Con *con_get_fullscreen_covering_ws(Con *ws);
+
 /**
  * Returns true if the container is internal, such as __i3_scratch
  *

src/click.c

@@ -254,7 +254,7 @@ static int route_click(Con *con, xcb_button_press_event_t *event, const bool mod
 
     /* 3: For floating containers, we also want to raise them on click.
      * We will skip handling events on floating cons in fullscreen mode */
-    Con *fs = (ws ? con_get_fullscreen_con(ws, CF_OUTPUT) : NULL);
+    Con *fs = con_get_fullscreen_covering_ws(ws);
     if (floatingcon != NULL && fs != con) {
         /* 4: floating_modifier plus left mouse button drags */
         if (mod_pressed && event->detail == XCB_BUTTON_CLICK_LEFT) {

src/commands.c

@@ -1282,7 +1282,7 @@ void cmd_focus_direction(I3_CMD, const char *direction) {
 static void cmd_focus_force_focus(Con *con) {
     /* Disable fullscreen container in workspace with container to be focused. */
     Con *ws = con_get_workspace(con);
-    Con *fullscreen_on_ws = (focused && focused->fullscreen_mode == CF_GLOBAL) ? focused : con_get_fullscreen_con(ws, CF_OUTPUT);
+    Con *fullscreen_on_ws = con_get_fullscreen_covering_ws(ws);
     if (fullscreen_on_ws && fullscreen_on_ws != con && !con_has_parent(con, fullscreen_on_ws)) {
         con_disable_fullscreen(fullscreen_on_ws);
     }

src/con.c

@@ -509,6 +509,23 @@ Con *con_get_fullscreen_con(Con *con, fullscreen_mode_t fullscreen_mode) {
     return NULL;
 }
 
+/*
+ * Returns the fullscreen node that covers the given workspace if it exists.
+ * This is either a CF_GLOBAL fullscreen container anywhere or a CF_OUTPUT
+ * fullscreen container in the workspace.
+ *
+ */
+Con *con_get_fullscreen_covering_ws(Con *ws) {
+    if (!ws) {
+        return NULL;
+    }
+    Con *fs = con_get_fullscreen_con(croot, CF_GLOBAL);
+    if (!fs) {
+        return con_get_fullscreen_con(ws, CF_OUTPUT);
+    }
+    return fs;
+}
+
 /**
  * Returns true if the container is internal, such as __i3_scratch
  *

src/handlers.c

@@ -310,16 +310,8 @@ static void handle_configure_request(xcb_configure_request_event_t *event) {
 
     DLOG("Configure request!\n");
 
-    Con *workspace = con_get_workspace(con),
-        *fullscreen = NULL;
-
-    /* There might not be a corresponding workspace for dock cons, therefore we
-     * have to be careful here. */
-    if (workspace) {
-        fullscreen = con_get_fullscreen_con(workspace, CF_OUTPUT);
-        if (!fullscreen)
-            fullscreen = con_get_fullscreen_con(workspace, CF_GLOBAL);
-    }
+    Con *workspace = con_get_workspace(con);
+    Con *fullscreen = con_get_fullscreen_covering_ws(workspace);
 
     if (fullscreen != con && con_is_floating(con) && con_is_leaf(con)) {
         /* find the height for the decorations */

src/manage.c

@@ -378,9 +378,7 @@ void manage_window(xcb_window_t window, xcb_get_window_attributes_cookie_t cooki
 
     /* handle fullscreen containers */
     Con *ws = con_get_workspace(nc);
-    Con *fs = (ws ? con_get_fullscreen_con(ws, CF_OUTPUT) : NULL);
-    if (fs == NULL)
-        fs = con_get_fullscreen_con(croot, CF_GLOBAL);
+    Con *fs = con_get_fullscreen_covering_ws(ws);
 
     if (xcb_reply_contains_atom(state_reply, A__NET_WM_STATE_FULLSCREEN)) {
         /* If this window is already fullscreen (after restarting!), skip

src/render.c

@@ -232,7 +232,7 @@ static void render_root(Con *con, Con *fullscreen) {
             continue;
         }
         Con *workspace = TAILQ_FIRST(&(content->focus_head));
-        Con *fullscreen = con_get_fullscreen_con(workspace, CF_OUTPUT);
+        Con *fullscreen = con_get_fullscreen_covering_ws(workspace);
         Con *child;
         TAILQ_FOREACH(child, &(workspace->floating_head), floating_windows) {
             if (fullscreen != NULL) {